While prowling AliExpress in search of novel stuff, I came across touch sensor switches for about 10¢ each quantity 50.

They are not new. The datasheet for the TTP223 chip at the heart of this module dates from August 2009. The attraction of this combo is that it is more than just a NO SPST switch. It can output either high or low level by selecting a solder jumper. Another solder jumper changes between momentary and toggle modes. The module also does switch debouncing, so you can skip doing that in the MCU firmware. It works with both 5 V and 3.3 V logic.

I connected one up to an Arduino (actually the ESP8266 Uno form factor equivalent) and verified that it works as advertised. I was at first disappointed because I had connected the module with jumper wires on a breadboard. But the proximity of the metal in the breadboard pin sockets disrupted the operation. Only when I moved it above the breadboard did it work. There is also a status LED on the back of the module which shines through the PCB a little. Depending on your application, this might or might not be annoying. You could always desolder the LED.

There is little point in describing setup and operation when there is a good resource from Instructables.

So, an alternative to the tactile switches I have been using, for a little more cost and surface area.